Hemodynamic and autonomic dysfunction in symptomatic carotid artery stenosis

Area of Science:

• Neurology
• Cardiovascular Science
• Vascular Medicine

Background:

• Steno-occlusive arterial disease, particularly carotid artery stenosis, is a significant stroke risk factor.
• Previous research suggests impaired autonomic function in patients with carotid artery stenosis.
• This study investigates autonomic dysfunction and cerebrovascular hemodynamics in patients with stenosis and suspected hemodynamic failure.

Purpose of the Study:

• To explore autonomic dysfunction and altered cerebrovascular hemodynamics in patients with steno-occlusive arterial disease and suspected hemodynamic failure.
• To assess the relationship between autonomic nervous system function and intracranial blood flow regulation during stress.

Main Methods:

• Autonomic nervous system function was assessed using heart rate variability (HRV) testing, an active stand test, and the Valsalva maneuver.
• Simultaneous monitoring of heart rate, blood pressure, and cardiac output was performed.
• Transcranial Doppler was used to measure relative changes in cerebral blood flow during the Valsalva maneuver.

Main Results:

• Patients with steno-occlusive carotid artery disease exhibited a significantly greater decrease in cerebral blood flow during the Valsalva maneuver compared to controls (0.80 ± 0.04 vs. 0.96 ± 0.05, p < 0.05).
• No significant differences in mean arterial blood pressure or heart rate were observed between patients and controls during the Valsalva maneuver.
• HRV analysis and the active stand test did not reveal significant autonomic dysfunction or orthostatic intolerance.

Conclusions:

• Patients with steno-occlusive carotid artery disease demonstrate impaired intracranial blood flow regulation during Valsalva-induced blood pressure reduction.
• The findings do not support the presence of significant autonomic dysfunction in patients with symptomatic large-vessel cerebrovascular disease, as assessed by HRV and active stand tests.